1. Field of the Invention
The present invention relates to a device for transmitting data in an installation for working fluids contained underground, the installation comprising a cavity defined in an underground formation and extending from the surface of the ground. The cavity is provided with at least one electrically conductive tubular element, and the device is of a type comprising a single-strand smooth cable for supporting an action and/or measurement assembly. The cable has a breaking strength greater than 300 decanewtons (daN), and is made of an electrically conductive material and disposed in the tubular element between a first point at the surface of the ground and a second point within the cavity. The invention also relates to an associated installation for working fluids contained underground.
The term “tubular element” is used to designate an element that is hollow and elongated, for example an element that is substantially cylindrical.
2. Description of Related Art
It is known to use single-strand smooth cables of the “piano wire” or “slickline” type to perform various mechanical operations (commonly referred to as “cable operations” or “slickline operations”) down an oil well or a well for some other effluent (in particular gas, steam, water). By way of example, such operations may be opening and closing valves, putting elements into place, or perforating a wall.
These cables which are referred to as “smooth cables” or “piano wire” in the present application, present the advantage of being simple to use. By their very nature they possess good mechanical properties, unlike twisted electrical cables. Providing sealing at the wellhead is significantly easier with “piano wire” type cables than it is with twisted electrical cables.
Nevertheless, use of such cables is limited to a mechanical function, and that can present drawbacks. For example, with perforation operations, when an explosive charge is lowered down a well at the end of a piano wire type cable, a timer is provided to trigger the explosive at the end of a predetermined length of time. Under such circumstances, an operator at the surface has no way of being sure that the explosion has indeed taken place, and when the cable is raised back to the surface, the tool may contain undetonated residual explosive, which can be dangerous.
Twisted electrical cables are also known that enable transmission of electrical signals. Nevertheless, such cables are more expensive, and handling them at a wellhead is more complicated than handling a smooth cable.